Shyness only begins to cover the range of social anxieties and social phobias covered by Schneier, assistant director of the Anxiety Disorders Clinic at the New York State Psychiatric Institute, and Welkowitz, a research psychologist also at the institute. There are fears of eating in public and of public bathrooms as well as fears of public speaking, dating, talking to the boss. There's probably more here than the average shy person looking for help wants, as about two thirds of the book is about the factors underlying shyness: biology, evolution, socialization, culture, sociology, psychology and so forth. There is also a chapter composed of tests that, while of excellent provenance, strangely make no distinctions between different sorts of social anxiety. The practical chapters that follow are worthwhile, especially when they stick to solid medical advice or therapy; social advice such as encouraging the wallflower to use ""seemingly corny"" openers--for example, ""Have I seen you somewhere before?"" and ""Come here often?""--is less so. In a system that prods readers to set specific, realistic goals each week and plot out how to attain them, the authors encourage exposure to unnerving situations and the developing of positive responses to replace (usually unacknowledged) negative ones. Also helpful is concrete advice to parents of shy children and a rundown of the effects and side effects of beta-blockers, benzodiazepines (e.g., Valium), SSRIs (e.g., Prozac) and MAOIs (e.g., Nardil). (Sept.)